Free Chlorine Maintained System

ABSTRACT

A method of maintaining a safe free chlorine level in a body of water for recreational use where the free chlorine level at a harmful level comprises determining if the free chlorine level in the body of water is above a safe level and adding sufficient DMH to the body of water to bring the free chlorine down to a safe level.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a division of Ser. No. 17/300,204 filed Apr. 12,2021 which claims priority from Ser. No. 16/602,276 filed Sep. 5, 2019which claims priority from provisional application Ser. 62/765,681 filedSep. 17, 2018.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

None

REFERENCE TO A MICROFICHE APPENDIX

None

BACKGROUND OF THE INVENTION

One of the difficulties in using chlorine for maintaining a body ofrecreational water at a person friendly condition i.e. such as a pool orhot tub, is that if the free chlorine level is too high it can beharmful to the persons in the body of recreational water. On the otherhand if the free chlorine level is too low the pathogens in the body ofrecreational water can be harmful to the persons in the body ofrecreational water. Typically, chlorine is continually added to a bodyof water such as pool or spa in a variety ways, for example through afloating dispenser or an inline dispenser that contains chlorine in asolid form. In these types of dispensers the rate of delivery ofchlorine is manually set to accommodate an expected load on the pool andis periodically adjusted based on tests on the amount of chlorine in thewater. One of the difficulties with free chlorine maintenance in asystem is the need to maintain the body of water in a person friendlycondition even though the body of water is subject to periodic batherloads, which consumes available free chlorine and therefore lessens thecapacity of the system to rid the body of water of harmful pathogens.Consequently, to maintain a body of recreational water in a personfriendly condition usually requires adding additional chlorine to thebody of water to replace the free chlorine consumed in ridding the waterof harmful pathogens. Various methods are used to maintain an acceptablelevel of free chlorine in the body of water as the demand for freechlorine varies in response to a bather load. One method useselectrolytic cells that generate additional chlorine. Another methoduses dispensers that can be adjusted to dispense additional chlorineinto the body of water in response to an increased bather load whilestill other methods may supplement the free chlorine with otherchemicals or metallic ions to maintain the body of recreational water ata person friendly condition i.e. where the free chlorine in the body ofwater continues to rid the water of harmful pathogens even though thebody of recreational water is subject to a periodic bather load.Typically, such systems require the pool owner to manually adjust thechlorine-dispensing rate before and after pool events if the pool ownerwants to maintain the body of water in a person friendly condition.

SUMMARY OF THE INVENTION

A free chlorine maintained system and a method of maintaining a freechlorine level in a body of water as the free chlorine is consumed withthe invention further including a free chlorine maintainer, which isself-regulating, for maintaining a free chlorine level in a body ofrecreational water for human immersion with the free chlorine level inthe body of water maintained at sufficiently low concentration to avoidchlorine harm to a person in the body of water and at sufficiently highconcentration to control the pathogens in the body of recreational waterat a safe level for human immersion even though the body of water issubject to periodic bather loads. It has been found that the addition of5, 5-dimethyl-hydanteoin (DMH), which is classified as an inert productsince it contains no antimicrobial properties, produces aself-correcting effect in response to increased chlorine requirementscaused by periodic bather loads on a pool. While not fully understood itis believed the system temporarily neutralizes chlorine being dispensedto the pool when the chlorine demand in the pool is normal and releasesthe neutralized chlorine in the form of free chlorine in response to anabnormal chlorine load to thereby eliminate the need to periodically addadditional chlorine to the body of water in response to a periodicbather loads. A further feature of the invention is that when the DMH isused in an outdoor pool the DMH can be accompanied by an algaecide tofurther maintain the pool free of algae in response to periodic batherloads. In order to maintain the self-correcting effect in response toperiodic bather loads DMH is periodically added to the body of water.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a table of the chlorine content in a 400-gallon Hot SpringsVanguard spa containing tap water and chlorine where the chlorine isobtained from Sodium Dichloroisocyanurate-dihydrate (Dichlor) and the pHof the water has been adjusted by adding pH down (sodium Bisulfate) tothe tap water;

FIG. 2 is a graph of the free chlorine in the 400-gallon Hot SpringsVanguard spa as a function of time with the spa having been subjected toa bather load and with the free chlorine in the water obtained fromSodium Dichloroisocyanurate-dihydrate;

FIG. 2A is a graph of the free chlorine in the 400-gallon Hot SpringsVanguard spa as a function of time with the spa having been subjected toa bather load and with the spa water containing 5,5-dimethyl-hydanteoin(DMH) and free chlorine obtained from SodiumDichloroisocyanurate-dihydrate;

FIG. 3 is a graph of the free chlorine in the 400-gallon Hot SpringsVanguard spa as a function of time with the spa having been subjected toa bather load with the water in the spa containing SodiumDichloroisocyanurate-dihydrate but no DMH;

FIG. 3A is a graph of the free chlorine and total chlorine in the400-gallon Hot Springs Vanguard spa as a function of time with the spahaving been subjected to a bather load with the water in the spacontaining both Sodium Dichloroisocyanurate-dihydrate and DMH;

FIG. 4 is a table of the contents of a 300-gallon Marquis Destiny Spacontaining tap water, Dichlor, DMH and pH down;

FIG. 5 is a graph of the free chlorine and total chlorine as a functionof the amount of DMH in the 300-gallon Marquis Destiny Spa;

FIG. 6 shows a dispenser partly in section with the dispenser containinga chlorinating agent and DMH for placement of the dispenser directly ina body of water;

FIG. 7 shows a two part dispensing system for separate placement of achlorinating agent and DMH into a body of water with each dispenserpartly in section;

FIG. 8 is a perspective view showing a dispersal valve for normally andcontrollable dispersing multiple water treatment dispersants into a bodyof recreational water;

FIG. 8A shows a kit;

FIG. 9 shows a partial cutaway perspective view of an annular nestablecanister supporting water treatment minerals therein for use in thedispersal valve of FIG. 8;

FIG. 10 shows a partial cutaway side view of a second nestable canistercontaining a chlorinating agent therein for use in the dispersal valveof FIG. 8;

FIG. 11 is an exploded view showing the second nestable canister of FIG.10 axially inserted within the nestable canister of FIG. 9 for use inthe dispersal valve of FIG. 8;

FIG. 12 shows a partial cutaway side view of a second nestable canisterquickly dispensable DMH therein for use in the dispersal valve of FIG.8; and

FIG. 13 shows a partial cutaway side view of a second nestable canistercontaining an immediate dispensable algaecide therein for use in thedispersal valve of FIG. 8.

DESCRIPTION OF THE PREFERRED EMBODIMENT

A free chlorine maintainable system, which is self-regulating, formaintaining a free chlorine level in the body of recreational watersufficiently low to avoid chlorine harm to a person in the body of waterand sufficiently high to control the pathogens in the body of water at asafe level when the body of water is subject to periodic bather loadswhile minimizing or eliminating the need to supply additionaldisinfectants to the body of water in response to the periodic batherloads. A body of recreational water as used herein, although not limitedto, is understood to comprise a body of water such as a pool, a spa ahot tub or the like in which a person wholly or partially immerseshimself or herself. While the invention described herein is suitable foruse in various bodies of water it is well suited for seasonal outdoorpools where the chlorine needs of the outdoor pool can vary for avariety of reasons including bather load and environmental loads.

It has been found that a free chlorine maintained system of recreationalwater using a free chlorine maintainer consisting of chlorine anddimethylhydantoin (DMH) while the physical conditions of therecreational water such as the temperature, the alkalinity and the pHare kept within limits acceptable for recreational use can maintain thebody of recreational water in a safe condition for recreational uses.The free chlorine maintained system allows the free chlorine in the bodyof water to attack the pathogens from the bather load while alsopreventing the free chlorine level in the body of water from dropping toan unsafe level, typically less than 0.5 to 0.1 ppm.

The inventions includes multiple ways of obtaining a water system thatavoids the drop off in free chlorine levels when the water is subjectedto a bather load. In order to provide examples of the invention a firsttest (chlorine without DMH) was conducted to show the free chlorinelevel in a body of water, which was subjected to a bather load. A secondtest (chlorine with DMH) was conducted to show the response of the freechlorine level in a body of water, which was subjected to a similarbather load when both chlorine and DMH are present in the body of water.

Example 1 (Chlorine without the Use of DMH)

The container for the body of recreational water was a 400-gallon HotSprings® Vanguard® brand spa. The procedure for preparing test water wasas follows:

-   -   1) Fill container with fresh tap water, with softener partially        bypassed to give approximately 200 parts per million of calcium        hardness. Measure and record calcium hardness.    -   2) Adjust temperature setting to 85 degrees Fahrenheit.    -   3) Add Sodium Bisulfate “pH Down” to adjust alkalinity into the        80-120 ppm range.    -   4) Add Sodium Dichloroisocyanurate dihydrate “dichlor” to        overcome the initial chlorine demand of the water.    -   5) After 1 day, adjust pH into the 7.2 to 7.8 range by running        the jets.    -   6) Measure & record temperature

For the test with dichlor the procedure was as follows:

-   -   1) Adjust free chlorine residual into the 0.5 to 1.0 ppm range.    -   2) Measure and record chlorine residuals, pH, and total        alkalinity    -   3) Have 2-4 bathers sit in the spa for 15-20 minutes. Record #        of bathers and time.    -   4) Allow 30 minutes to pass, then measure and record chlorine        residuals.    -   5) Allow 1 more hour to pass, then measure and record chlorine        residuals.

The container was filled with fresh tap water, with softener partiallybypassed and tested using a Taylor® kit K-2006 Calcium Hardness droptest which measured water hardness of approximately 200 parts permillion of calcium hardness.

The total Alkalinity of the recreational water was measured using aTaylor® kit K-2006 Alkalinity drop test. To adjust the total alkalinitylevels of the water to the 80-120 ppm range 95% Sodium Bisulfate (pHDown) was added to the water. The 95% Sodium Bisulfate, which was addedto the body of recreational water, was obtained from Great LakesBiochemicals®. To add chlorine to the body of recreational water in thecontainers 99% Sodium Dichloroisocyanurate dihydrate (dichlor) was addedto the water. The 99% Sodium Dichloroisocyanurate dihydrate was obtainedfrom Great Lakes Biochemicals®, and applied to the body of water toovercome the initial sanitizing chlorine demand of the water in thecontainer. As used herein the term Dichlor refers toDichloroisocyanurate dihydrate and the term DMH refers to 5-5dimethylhydantoin while the reference in ppm is to parts per million byweight.

The water temperature in the container was measured using a Thermoworks®Superfast Digital Thermometer and the water in the container wasmaintained at about 85° F. The water in the containers was allowed tostabilize for a day after which the pH levels of the water in thecontainer was measured using an Oakton® EcoTestr pH2 meter. To adjustthe pH level in the body of water the pH jets in each of the containerswere run until the pH level in each of the containers was within therange of 7.2 to 7.8.

FIG. 1 shows a table of the results of the test (with and without DMH)where the free chlorine, the total chlorine, the pH, the totalalkalinity and the temperature were measured after 400-gallon HotSprings® Vanguard brand spa and pH down had been added to the spa waterin a 400-gallon Hot Springs® Vanguard® brand spa.

FIG. 2 shows a graph of the free chlorine as a function of time with the400-gallon Hot Springs® Vanguard brand spa (without DMH) which containsDichlor as the spa water is subjected to a bather load. As can be seenthe level of free chlorine declines from 1 ppm to about 0.1 ppm inresponse to the bather load.

FIG. 2A shows a graph of the free chlorine as a function of time withthe 400-gallon Hot Springs® Vanguard® brand spa which contains Dichlorand DMH as the spa water is subjected to a bather load. As can be seenthe level of free chlorine remains in a range of about 0.7 ppm to 0.6ppm in response to the bather load.

FIG. 3 shows a graph of the free chlorine and the total chlorine as afunction of time with the 400-gallon Hot Springs® Vanguard brand spawhich contains Dichlor and no DMH as the spa water is subject to abather load that creates an immediate need for free chlorine toneutralize the effects of bathers in the pool. As can be seen the levelof both the free chlorine and the total chlorine declines with the freechlorine declining to 0 ppm while the total chlorine declines from 1.0ppm to about 0.5 ppm in response to the bather load. The reference toppm used herein is in reference to ppm by weight.

FIG. 3A shows a graph of the free chlorine and the total chlorine as afunction of time with the 400-gallon Hot Springs® Vanguard® brand spawhere the spa water contains chlorine introduced through the addition ofDichlor and DMH as the spa water is subject to a bather load. As can beseen the level of the free chlorine remains between 1.0 ppm and 0.5 ppmwhen the spa water is subject to the bather load while the totalchlorine declines from about 8.5 to about 7.5 as the spa water issubject to the bather load.

Thus the invention described herein in one example comprise a method ofmaintaining the free chlorine in a body of water for human immersionbetween 0.5 ppm and 1 ppm when subject to a bather load that decreasesthe free chlorine available in the pool. In this mode the inventioncomprises the steps of adding a chlorinating agent to overcome theinitial sanitizing chlorine demand of the body of water and maintaininga temperature of the body of water between degrees 70° F. to 104° F. Ifneeded one can adjust the alkalinity of the body of water to between 80ppm and 120 ppm by adding sodium bisulfate. Preferably one shouldmaintain the pH in the body of water in the range of 7.2 to 7.8. Withthe above methods one can add chlorine to the body of water to bring thetotal chlorine level in the body of water to between 1-20 ppm. In thisexample it has been found that if one adds DMH to the body of water onecan bring the level of free chlorine to about 1 ppm as the addition ofDMH has been found to lower the measurable free chlorine until a stableor equilibrium state of about 1.0 ppm is obtained. Once the initialchlorine conditions of the pool are established a maintenance amount ofchlorine can be continually or intermittingly added to the body of waterthrough a dispenser or the like to maintain the body of water in theinitial condition for human recreational use. Typically, the rate ofrelease of chlorine is manually selected on either an inline dispenseror an in water dispenser in order to maintain a free chlorine base(typically 0.5 ppm to 1.0 ppm free chlorine) in the body of watersufficient to maintain the pool suitable for use by bathers. With theabove-described chlorine base water condition maintained through adispenser, which is not responsive to a bather load it has been foundthat with the presence of DMH and chlorine in the body of water one cansubject the body of water to a normal bather load, which although thebather load spikes the need for free chlorine the use of DMH andchlorine prevents the free chlorine level dropping to an unacceptablelevel. That is, it has been found that while the bather load absorbsfree chlorine in the body of water, with the presence of DMH the levelof free chlorine is prevented from decreasing to less than 0.5 ppm. Anormal bather load as described herein is bather use that is unique to aparticular pool use and may be different for another pool. For example,some pools may have two persons using the pool on a regular basis whileother pools may have six or seven people using the pool on a regularbasis. In each case once the base level of chlorine has been establishedthe use of chlorine in combination with the DMH can be used to provide abuffer to maintain the pool water in a person friendly condition eventhough the bather load has spiked the need for additional chlorine toaccommodate the effects of the bathers in the pool.

One of the features of the invention is that the addition of DMH to thebody of recreational water, which contains chlorine, causes the freechlorine level in the body of water to reach an equilibrium state eventhough the temperature of the body of water may range from 70° F. to104° F. Once the equilibrium state is reached the free chlorine as wellas the total chlorine in the body of recreational water has been foundto remain constant as the amount of DMH is increased. To illustrate thisfeature reference should be made to the example two, which is shown ingraph form in FIG. 5. That is, FIG. 5 shows both the free chlorine andthe total chlorine in the body of water as a function of the amount ofDMH in the water with the level of free chlorine decreasing to about 0.5ppm and remaining at 0.5 ppm as additional DMH is added to the body ofwater.

Example 2

In this example a 300 gallon Marquis Destiny spa was filled with tapwater with pH down added to the body of water to adjust the pH of thewater. The use of a 300 gallon spa for testing was for convenience sincethe use of both dimethylhydantoin (DMH) and Dichlor are scalable featurethat applies to large bodies of water such as pools as well as smallerbodies of water such as hot tubs, spas or the like. In this example bothdimethylhydantoin (DMH) and Dichlor in solid form were added directly tothe body of water and the free chlorine and the total chlorine weremeasured and recorded as a function of amount of DMH in the 300-gallonMarquis Destiny spa. Although Dichlor and DMH were added to the body inbulk form various methods and forms of adding chlorine and the DMH tothe body of water may be used including dispensers and water dissolvablecontainers.

The test procedure for Example 2 was as follows:

I. General

-   -   1) Record all measurements and chemical additions. The chemical        additions shall be made immediately after the measurements are        recorded.    -   2) Chemical additions shall be made by broadcasting over the        surface while all of the jets are running in order to fully mix        them throughout the body of water.

II. Startup

-   -   1) Fill with fresh tap water, with softener partially bypassed        to give approximately 200 parts per million of calcium hardness.    -   2) Adjust temperature setting to 85 degrees Fahrenheit.    -   3) Add Sodium Bisulfate “pH Down” to adjust alkalinity into the        80-120 ppm range.    -   4) Add Sodium Dichloroisocyanurate-dihydrate “dichlor” to        overcome the initial chlorine demand of the water.    -   5) If needed, adjust pH into the 7.2 to 7.8 range by running the        jets.    -   6) Measure & record temperature

III. Free Chlorine vs. DMH Test

-   -   1) Adjust the free chlorine residual to approximately 10 ppm.    -   2) Measure and record chlorine residuals, pH, and total        alkalinity.    -   3) Incrementally increase DMH concentration and record residuals        & pH.

FIG. 4 shows a table of the results of the measurements of the total andfree chlorine in the 300-gallon Marquis Destiny spa as well as the DMHin the body of water.

A reference to FIG. 5, which shows a graph of the free chlorine and thetotal chlorine as a function of the amount of DMH in the water showsthat the total chlorine remains above 9 ppm as the DMH is increased from1 to 200 ppm. On the other hand the free chlorine drops to about 0.5 ppmand remains at about 0.5 ppm as the concentration of DMH in the body ofwater is increased from 20 to 200 ppm.

To verify the benefit of the use of DMH tests were conducted in aseasonal outdoor pool to determine the response to environmental loadsas well as to period bather loads. In the first step the waterconditions of an outdoor pool was set up that includes:

-   -   1. Initially setting the water temperature of the pool about        85° F. although the water temperature will fluctuates due to        outside weather conditions    -   2. Adjusting the Calcium Hardness of the pool water to 200 ppm    -   3. Adjusting the Alkalinity of the pool water to be within the        range of 80-120 ppm    -   4. Adjusting the pH of the pool water to be within the range of        7.2 to 7.8

The above base conditions are typical of a pool set up conditions andcreated through the use of known pool products in order to create a bodyof water that is suitable and comfortable for use by an individual or agroup of individuals and in some instances the base conditions may bechanged for the convenience of the pool owner without departing from thespirit and scope of the invention as long as the total chlorine levelcan be reduced to a free chlorine level of about 1 ppm or less throughthe addition of DMH to the body of water.

Once the pool water is prepared for human use a sufficient amount of DMHis added to the pool water to bring the DMH concentration in the pool upto 200 ppm. While more or less DMH may be used it is preferred to haveat least 200 ppm since the DMH eventually degrades during pool use.Typically, under most pool use an initial dose of 200 ppm of DMH lastsabout 30 days. It is noted that it is further preferred to have the DMHconcentration in the pool maintained between 20 ppm and 200 ppm, whichmay also be referred to as a “working” concentration or of DMH.

In the next step chlorine is added to the water containing the DMH tobring the total chlorine level up to at least 5.0 ppm, which has beenfound to raise the level the free chlorine in the water to 0.5 to 1.0ppm. Chlorine may be added to the water in the pool in several differentways including but not limited to 1. liquid bleach (NaClO), 2. Calciumhypochlorite (CA(ClO)) or 3. Trichloroisocyanauric acid (C3Cl3N3O3). Anunknown relationship exists between the chlorine and the DMH that causesthe free chlorine in the pool to stabilized and be maintained between alevels of 0.5 to 1.0 pm as shown in FIG. 5. In addition although thefree chlorine level is maintained between 0.5 and 1.0 ppm it has beenfound that the likely relationship between the DMH and the attached orcombined chlorine in the body of water forms a reservoir of chlorinethat can be used to compensate for the excess free chlorine use requiredby a periodic chlorine load on the pool. For example, by periodic loadit is understood to include a need for additional free chlorine tocompensate for the use of pool by a group of people although other typesperiodic loads, which consume chlorine, may also be compensated for withthe invention described herein.

In the next step the operator adjust the chlorine dispenser to deliver aconstant rate of chlorine into the pool. The delivery of a constant rateof chlorine is intended to balance the ongoing needs of the pool as itresponds the external environment and is considered a base level tohandle the typical ongoing chlorine needs of the pool.

During use of the pool the operator periodically tests the level ofchlorine and adjust the rate of chlorine release from a dispenser inevent the ongoing chlorine needs of the pool changes. For example, theongoing chlorine needs of the pool may change due to sunlight or organicdebris that may enter the pool, such as but not limited to after astorm. These types of changes in chlorine needs are considered long-termchanges and are compensated typically through a manual adjustment of theamount of chlorine delivered to the pool.

After a set period (30 days preferred) additional DMH may be needed tobe added to the pool to bring the concentration of DMH in the pool backto a “working” concentration or the effect of maintaining a reservoir offree chlorine is lost as the DMH decreases with time. The pool with theDMH is now set to handle the periodic spikes or loads on the pool due toperiodic bather use

Under some conditions the algae growth in pool may cause an increase infree chlorine use that cannot be overcome by the chlorine reservoir(attached chlorine-DMH reservoir). At this point one can add analgaecide to the pool water.

Because the DMH effectiveness in neutralizing the free chlorinedecreases it becomes necessary to replenish the DMH after a period oftime.

A feature of the invention described herein is that there are a numberof ways one can obtain a free chlorine maintained system. A freechlorine maintainer, which comprises a chlorinating agent and DMH, canbe separately introduced into the body of recreational water for the insitu formation of the free chlorine maintainer in the body ofrecreational water. In one example DMH is added to the body of waterfollowed by the addition of a chlorinating agent until the chlorinereaches an equilibrium state at about 1.0 ppm. In another examplechlorine is added to the body of recreational water followed by theaddition of sufficient DMH to bring the chlorine into an equilibriumstate, which is about 1 ppm. In still another example the DMH andchlorine agent may be simultaneously delivered to the body of watereither in bulk form or through a container that is thrown or placed inthe body of water, for example a container that dissolves in the body ofwater to release the chlorinating agent and dimethyl hydantoin. Thusthere are multiple ways one can obtain a free chlorine maintainedsystem.

In the example described a chlorinating agent such as sodiumdichloroisocyanurate dihydrate is added to the body of water beforedimethylhydantoin (DMH) is added. Typically, sufficient chlorinatingagent should be added to the body of water to bring the free chlorinelevel in the body of water to at least 1.0 ppm but less than 20 ppm.Subsequently, sufficient dimethylhydantoin (DMH) should be added to thebody of water to bring the free chlorine level in the body of water toan equilibrium state of about 1.0 ppm. Typically, adding sufficientdimethylhydantoin to bring the dimethylhydantoin concentration in thebody of water to at least 20-ppm results in a free chlorine equilibriumstate ranging from about 0.5 ppm to 1.0 ppm. Increasing theconcentration of dimethylhydantoin in the body of water from 20 ppm to200 ppm has not been found to reduce the free chlorine equilibrium inthe body of water.

In one method of the invention dimethylhydantoin (DMH) is separatelyadded to the body of water followed by the separate addition of thechlorinating agent. It has been found that both the DMH and freechlorine in the body of water degrade with time one method ofmaintaining the body of water is to periodically add DMH and chlorine tothe body of water. This maintenance additions of DMH and chlorine may bedone separately or at the same time.

The invention also includes a method of maintaining the free chlorine ina body of water for human immersion between 0.5 ppm and 1.0 ppm whileother features of the water are maintained as the water is subject to abather load that normally decreases the free chlorine. Preferably onewants to add a chlorinating agent to overcome the initial sanitizingchlorine demand of the body of water. Typically, one maintains atemperature of the body of water between degrees 70° F. to 104° F. whileit is preferred to adjust the alkalinity of the body of water to between80 ppm and 120 ppm, for example by adding sodium bisulfate. It is alsofor comfort it is preferred to maintain the pH in the body of water inthe range of 7.2 to 7.8. Typically, in one method one adds chlorine tothe body of water to bring the total chlorine level in the body of waterto between 1-20 ppm and then adds DMH to the body of water to bring thelevel of free chlorine down to about 1.0 ppm. One can then subject thebody of water to a normal bather load or other type of normal load, suchas from rain. Although the typical load placed on the body of water,which absorbs free chlorine in the body of water, has been found to notdecrease the free chlorine less than 0.5 ppm. As described herein thetypical load for a body of water may vary and consequently the timebetween additions of chlorine may vary from spa to spa. For example, insome cases the free chlorine level may reside at appropriate levels fora period of months based on the typical bacterial load and in othercases the free chlorine level may last for a period of weeks due to theheavier bacterial load. In each case the primary determination of theadditional length of time that the system maintains itself at safe freechlorine level is to a certain extent determined by the bacterial loadnormally experienced by the body of water.

A feature of the invention described herein is that in systems where thefree chlorine have been purposely or accidentally raised to levels thatare considered harmful for recreation use, which some sources indicatesas being as low as 2.5 ppm, the body of water can be rendered suitablefor recreational use through the addition of DMH to the body of water.In the example shown in FIG. 4 and FIG. 5 the free chlorine level in thebody of water is lowered through the addition of DMH to the body ofwater. Note FIG. 4 shows a free chlorine level in excess of 10 ppm beinglowered to 0.52 ppm through the addition of DMH to the body of water.Thus the use of DMH becomes effective to reduce the level of freechlorine in a pool without having to increase the bacterial load on thepool.

In one example the invention can comprise a one-shot prepackaged freechlorine maintainer for emptying into a body of water such as a spa orpool to maintain a free chlorine level in the body of water between 0.5ppm and 1.0 ppm when the body of water is subject to a bather load withthe free chlorine maintainer consisting of a chlorinating agent in solidform and DMH in solid form where a weight ratio of the DMH to thechlorinating agent in the body of water is at least 0.5.

While the chlorinating agent described herein comprises sodiumdichlorocyanurate dihydrate other chlorinating agents may be used toestablish the free chlorine level in the body of water. For example achlorinating agent selected from the group consisting of both organicand inorganic agents including trichloroisocyanauric acid, potassiumdichloroisocyanurate, dichlorocyanurate dihydrate, calcium hypochlorite,lithium hypochlorite and sodium hypochlorite.

FIG. 6 shows a prepackaged free chlorine maintainer for emptying into abody of water to maintain free chlorine level in the body of waterbetween 0.5 ppm and 1.0 ppm when the body of water is subject to abather load with the free chlorine maintainer consisting of achlorinating agent in solid form and DMH in solid form where a weightratio of the DMH to the chlorinating agent in the body of water is atleast 0.5 In this example the container 10 has a first compartment 10 athat contains the chlorinating agent 11 with the container 10 havingports 14 for water access to the chlorinating agent therein and a secondcompartment 10 b that contains DMH 12 with ports 15 therein to permitwater access to the DMH therein. While the DMH and chlorinating agentare added from the same dispenser they also can be added separately andat different times and the chlorine may be added to the body of watereither in solid or liquid form.

FIG. 7 shows another example of a spa product for maintaining the freechlorine level between 0.5 ppm and 1.0 ppm in a body of water subject toa bather load with the spa product. In this example there is provided afirst dispenser 30 having a compartment 31 containing a chlorinatingagent 32 selected from the group consisting of trichloroisocyanauricacid, potassium dichloroisocyanurate, and sodium dichlorcyanurate withthe dispenser having at least one port 30 a for water access to thechlorinating agent therein when the dispenser 30 is placed in the bodyof water. In this example the spa product includes a second dispenser 33with a compartment 35 containing dimethylhydantoin 34 with the seconddispenser 33 having at least one port 33 a for water access for releaseof the dimethylhydantoin into the body of water.

While the dispenser are shown as the type that are placed directly inthe body of water the dispenser may be of the inline type that is placedin a dispenser where water is circulated through the dispenser. Examplesof such dispensers are shown in King et al. U.S. Pat. Nos. 7,347,935 and8,464,743, which are incorporated by reference.

Various chemical chlorinating agents are disclosed herein that aredispensed into the body of water, however, in some instance one may findit suitable to use a chlorine generator. While in water dispensers areshown one may want to use a bulk dispenser where the water is directedthrough a dispersant located in the bulk inline dispenser. Examples ofbulk inline dispensers are shown in king U.S. Pat. No. 8,757,188, whichis hereby incorporated by reference.

Although not shown the present invention may also comprise a swimmingpool free chlorine maintaining kit for use in an inline dispenser of aswimming pool body of water that has been sanitized with a chlorinatingagent to render the body of water safe for human immersion and subjectto a periodic bather load and environmental conditions.

The swimming pool free chlorine maintaining kit includes a firstdispensing cartridge and a second dispensing cartridge each separatelyloadable into the inline dispenser of the swimming pool body of water.

The first dispensing cartridge includes a bottom inlet and a bottomoutlet and contains an immediate dispensable or quickly dispensable DMHsupported therein in sufficient amount to bring a DMH level in theswimming pool body of water to at least 26 ppm. By immediate dispensableor quickly dispensable, it is meant that the DMH is completelydispensable into the swimming pool body of water within 30 minutes andpreferably within 15 minutes.

The second dispensing cartridge includes a bottom inlet and a bottomoutlet and contains a time dispensable chlorinating agent therein tobring the total chlorine level in a swimming pool body of watercontaining at least 26 ppm DMH to between 3.0 and 10 ppm total chlorinewith the concentration of DMH maintaining a free chlorine level in theswimming pool body of water to a range 0.5 ppm to 1.0 ppm free chlorine.

The swimming pool free chlorine maintaining kit may also include a thirddispensing cartridge separately loadable into the inline dispenser ofthe swimming pool body of water with the third dispensing cartridgecontaining a time dispensable combination chlorinating agent andalgaecide dispensable into the swimming pool body of water in responseto a decrease of the free chlorine level in the swimming pool body ofwater to less than 0.5 ppm free chlorine to kill existing algae andcontrol algae growth in the body of water while bringing the totalchlorine level in the swimming pool body of water back to between 3.0and 10 ppm.

The third dispensing cartridge may alternatively contain an immediatedispensable algaecide therein, the algaecide dispensable into theswimming pool body of water at the sign of algae growth to kill existingalgae and control algae growth in swimming pool body of water.

The present invention also includes a method of maintaining the freechlorine in a body of water for human immersion between 0.5 ppm and 1.0ppm when subject to a bather load and environmental conditions thatdecreases the free chlorine comprising the steps of (1) maintaining atemperature of the body of water between degrees 70° F. to 104° F., (2)sanitizing the body of water with a chlorinating agent to render thebody of water safe for human immersion, (3) adjusting the alkalinity ofthe body of water to between 80 ppm and 120 ppm by adding either sodiumbicarbonate to raise the alkalinity or muriatic acid to lower thealkalinity, (4) maintaining the pH in the body of water in the range of7.2 to 7.8, (5) loading a first dispensing cartridge containing animmediate dispensable DMH therein into an inline dispenser of the bodyof water to bring a DMH level in the body of water to at least 26 ppm,(6) loading a second dispensing cartridge containing a time dispensablechlorinating agent therein into the inline dispenser of the body ofwater to bring the total chlorine level in a body of water containing atleast 26 ppm DMH to between 3.0 and 10 ppm total chlorine with theconcentration of DMH maintaining a free chlorine level in the swimmingpool body of water to a range 0.5 ppm to 1.0 ppm free chlorine, and then(7) subjecting the body of water to a bather load where the bather loadconsumes free chlorine and combined chlorine in the body of waterwithout decreasing the free chlorine to less than 0.5 ppm level.

The above method of maintaining the free chlorine in a body of water forhuman immersion between 0.5 ppm and 1.0 ppm when subject to a batherload and environmental conditions that decreases the free chlorine mayalso include the steps of (8) loading a third dispensing cartridgecontaining a time dispensable combination chlorinating agent andalgaecide therein into the inline dispenser of the body of water inresponse to a decrease of the free chlorine level in the body of waterto less than 0.5 ppm free chlorine to kill existing algae and controlalgae growth in the body of water while bringing the total chlorinelevel in the body of water back to between 3.0 and 10 ppm, (9) loading athird dispensing cartridge containing an immediate dispensable algaecidetherein into the inline dispenser of the body of water at the sign ofalgae growth water to kill existing algae and control algae growth inthe body of water, (10) loading a third dispensing cartridge containinga time dispensable combination chlorinating agent and algaecide thereininto the inline dispenser of the body of water at the sign of algaegrowth to kill existing algae and control algae growth in the body ofwater while bringing the total chlorine level in the body of water backto between 3.0 and 10 ppm, and (11) loading a third dispensing cartridgecontaining an immediate dispensable DMH therein into the inlinedispenser of the body of water to bring the DMH level in the body ofwater up to at least 20 ppm.

FIG. 8 shows an example of a dispersal valve 40 and FIG. 8A shows anexample of a seasonal pool water treatment kit 80 that contains fourcanisters 51, 60, 65 and 70, which are suitable for dispensing materialswhen they are located in dispersal valve 40. In this example theseasonal pool water treatment kit 80 comprises a set of four nestablecanisters 51, 60, 65 and 70 that can be periodically removed andreplaced in dispersal valve 40 to provide season long outdoor poolmaintenance for a pool, which is typically used in only the summermonths. A box or other type of container 81 may be used to both storeand deliver the seasonal pool water treatment kit to a consumer.

Referring to FIG. 8, reference numeral 40 general identifies a dispersalvalve for normally and controllable dispersing multiple water treatmentdispersants into a body of recreational water. Dispersal valve 40, whichis shown in greater detail in King U.S. Pat. No. 6,190,547, includes afluid inlet 42 on one side of a housing 41 and a fluid outlet 43 locatedon the opposite side of housing 41. A rotary plug 44 permits a user tocontrol the velocity of the fluid mixing stream that is directed throughthe dispersal valve 40 and through the nestable canisters located in thedispersal valve 40.

FIG. 9 shows a partial cutaway perspective view of an annular nestablecanister 50 for insertion into dispersal valve 40. Nestable canister 50is made from a rigid polymer plastic and normally stands in an uprightposition in a dispersal valve. In use the cylindrical nestable canister60 can be nested within the annular nestable canister 50, as illustratedin FIG. 11. In the nested condition the two canisters 50 and 60simultaneous deliver dispersant into the water flowing through thedispersal valve 40. Kit 80 also includes nestable canisters 65 and 70,which are shown in isolated and partial cut away views in FIG. 12 andFIG. 13. The three cylindrical nestable canisters 60, 65 and 70 (FIGS.10, 12, and 13) are interchangeable with each other and providedispersal valve 40 with multiple water treatment options for dispensingwater treatment materials into a body of recreational water. The use ofadditional interchangeable nestable canisters 65 and 70 provide for aconvenient seasonal system for on-the-go maintenance of an outdoor poolwith a minimum of maintenance. In this example, annular canister 50includes an outer cylindrical surface 51 that enables canister 50 to beaxially inserted into an interior chamber of dispersal valve 40. Inaddition, nestable canister 50 has a central open region where a secondnestable canister 60 can be functionally nested therein so that bothcanister 50 and canister 60 can simultaneously deliver dispersants tothe water flowing through the dispersal valve. FIG. 9 shows nestablecanister 50 also includes an annular chamber 54 defined by a cylindricalinner wall 52 and an outer cylindrical wall 53 with the annular chambersupporting typical water treatment materials such as minerals 55therein. An example of minerals can be found in King U.S. Pat. No.9,227,860, which is herby, incorporated by reference.

FIG. 10 shows a partial cutaway side view of a cylindrical nestablecanister 60. In the embodiment of FIG. 10, the cutaway view showsdispersants comprising a chlorinating agent 61 located within nestablecanister 60. Examples of chlorinating agent 61 include chlorine tablets,granular or in powder form for killing bacteria although other types ofchlorinating agents may be used. The operation of nestable canister 60is similar to the operation of nestable canister 50 with the operationof the nestable canister shown and described in King U.S. Pat. No.6,190,547, which is herby incorporated by reference.

FIGS. 10, 12 and 13 show examples seasonal dispersant canisters A, B andC that can be used to maintain a body of water such as a swimming poolduring a typical outdoor season through a periodic rotation orreplacement of canisters within the annular canister 50. In thisexample, the set of four canisters comprise an outer annular canister50, which contains a first dispersant and a set of interchangeablecanisters 60, 65 and 70, which can be individually fitted within annularcanister 50. FIG. 8A shows the interchangeable canisters comprising afirst cylindrical canister 60 (labeled A), which contains a seconddispersant, a second cylindrical canister 65 (labeled B), which containsa second dispersant and a third cylindrical canister 70 (labeled C)which contains a third dispersant. Although four canisters are shownmore or less canisters may be used depending on the type of seasonalwater treatment needed.

FIG. 11 is an exploded view showing how nestable canister 60 can beaxially inserted within a cylindrical chamber 50 a in the annularnestable canister 50. Nestable canister 60 includes an outer dimensiondesignated by W₁ and nestable canister 50 has an inside dimensiondesignated by W₂ with W₂ greater than W₁ so that canister 60 can befreely inserted within chamber 50 a in the interior of canister 50.Nestable canister 65 and 70 are similarly dimensioned so that they canbe inserted and removed from the annular nestable canister 50. Once inposition water directed through the bottom of the dispersal valve 40comes into contact with the dispersants in the annular canister 50 andthe cylindrical canister located within the annular canister 50.

FIG. 12 shows a partial cutaway side view of the second nestablecanister 65. In this example, Canister B contains DMH with the DMH in animmediate dispensable state or a quickly dispensable state. By“immediate dispensable” or “quickly dispensable”, it is meant that theDMH contained within the dispenser can be dispensed into the swimmingpool within 30 minutes or less and preferably within 15 minutes aftercoming into contact with the water. (need to explain source of DMH)

Once the DMH is dispensed into the body of water canister B is removedfrom canister 50 and replaced with canister A from the set of seasonalcanisters 50, 60 (canister A), 65 (canister B) and 70 (canister C).Canister A, which in this example contains a chlorinating agent 61 andthe canister 50 which contains minerals 55 can now simultaneouslydispense dispersant therein into the body of water to thereby seasonallymaintain the body of water as the water flows through the dispersalvalve containing the two canisters.

FIG. 13 shows a partial cutaway side view of the third nestable canister70 (canister C) with a dispersant 71 therein. In this example canister Ccontains a dispersant 71 comprising an algaecide 71. To add thealgaecide to the water the canister A in the nestable canister isremoved and replaced with canister C containing the algaecide therein tothereby deliver the algaecide into the body of water. Once the algaecideis dispensed the canister C is removed and is replaced by Canister A,which contains the chlorinating agent. In this example the algaecide incanister C is delivered into the body of water through the canister inthe dispersal valve, however, one may elect to deliver the algaecidedirectly into the body of water which eliminates the step of removingand replacing the canister A with canister C since the algaecide can beadded independent of the dispersal valve canisters.

Preferably, a quickly dispensable algaecide 71 is used. Once thealgaecide has been dispensed into the body of water the dispenser 71 isremoved and the dispenser A with the chlorinating agent is placed indispersal valve 40 to allow the chlorinating agent and the minerals tomaintain the pool water. While in this example the algaecide has beenintroduced through an interchangeable canister in some instances thealgaecide may be introduced into the pool independent of the dispersalvalve system. In such an example the algaecide may be packaged in anon-interchangeable dispenser that can dispense the algaecide directlyinto the pool.

As described herein the start-up phase of the pool water treatmentsystem begins with dispensing of the DMH, along with water treatmentminerals 55, into the outdoor swimming pool body of water by loadingnestable canister 50 and nestable canister 65 into dispersal valve 40and activating the dispersal valve 40. The amount of DMH 66 in nestablecanister 65 is determined by pool size such that the complete dispensingof the DMH 66 in nestable canister 65 brings the DMH level in theswimming pool to at least 26 ppm.

Once the DMH 66 in nestable canister 65 is spent the pool maintenancephase of the pool water treatment system begins with the introduction ofa chlorinating agent 61, along with water treatment minerals 55, intothe swimming pool through the replacement of the spent nestable canister65 with a fresh or new nestable canister 60. A feature of the presentinvention is that chlorinating agent 61, which is time dispensableenables one to bring the total chlorine level in a swimming pool body ofwater to between 3.0 and 10 ppm with the concentration of DMH, which isabout 26 ppm, maintaining a free chlorine level in the swimming poolbody of water to a range 0.5 ppm to 1.0 ppm free chlorine.

A pool booster phase, which may be used in some cases, begins with theaddition of an algaecide. The pool booster phase is an optional ondemand phase that generally occurs in response the presence of algaegrowth leading to a decrease of the free chlorine level in the swimmingpool body of water to less than 0.5 ppm free chlorine. The pool boosterphase may be addressed with the aforedescribed introduction of animmediate dispensable algaecide 71, along with water treatment minerals55, into the swimming pool body of water through the replacement ofnestable canister 60 (canister A) with nestable canister 70 (canister Ccontaining the algaecide) to kill existing algae and control algaegrowth in the body of water while bringing the total chlorine level inthe swimming pool body of water back to between 3.0 and 10 ppm. Once thealgaecide in nestable canister 70 is dispensed into the pool the spentnestable canister 70 is replaced with the nestable canister 60 unlessnestable canister 60 is also empty. In the event that canister 60 isalso empty the spent nestable canister 70 is replaced with a fresh ornew canister 60 that contains a fresh amount of chlorinate agent.

The pool booster phase starts with the introduction of an immediatedispensable algaecide 71, along with water treatment minerals 55, intothe swimming pool body of water through the replacement of nestablecanister 60 with nestable canister 70 to kill existing algae and controlalgae growth in the body of water while bringing the total chlorinelevel in the swimming pool body of water back to between 3.0 and 10 ppm.Once the algaecide is completely dispensed the spent nestable canister70 is replaced with the used nestable canister 60 unless nestablecanister 60 is also empty. In the event that canister 60 is also emptythe spent nestable canister 70 is then replaced with a fresh or newcanister 60.

As an alternative, instead of having the algaecide in nestable canister70 the algaecide may be directly poured into the pool. In this examplethe canister with the chlorinating agent 60 need not be removed from thedispersal valve 40 during the delivery of the algaecide to the pool.

Thus, in a typically outdoor pool season the pool owner may first useCanister B in annular canister 50 followed by canister A, which isfollowed by canister C, which is again followed by canister B. Thus thekit 80 provides a convenient way for maintaining an outdoor poolthroughout the outdoor season without the need with the pool ownerhaving to come into contact with the pool chemicals.

The inventions described herein includes a number of methods ofmaintaining the free chlorine in a body of water for human immersionbetween 0.5 ppm and 1.0 ppm when subject to a bather load that consumesthe free chlorine. In one method one adds a chlorinating agent toovercome the initial sanitizing chlorine demand of the body of waterwhile maintaining a temperature of the body of water between degrees 70°F. to 104° F. One adjusts the alkalinity of the body of water to between80 ppm and 120 ppm by adding either sodium bicarbonate to raise thealkalinity or muriatic acid to lower the alkalinity while maintainingthe pH in the body of water in the range of 7.2 to 7.8. One addschlorine to the body of water to bring the total chlorine level in thebody of water between 1-20 ppm followed by adding DMH to the body ofwater to bring the level of free chlorine to about 1 ppm. At this pointone can subject the body of water to a bather load where the bather loadconsumes free chlorine and combined chlorine in the body of waterwithout decreasing the free chlorine level to less than 0.5 ppm. Themethod may include adding chlorine to the body of water to bring thetotal chlorine level in the body of water between 1-20 ppm by addingchlorine from the group consisting of trichlor, calcium hypochlorite,sodium hypochlorite and sodium dichloroisocyanurate dihydrate to thebody of water to bring the free chlorine level in the body of water toat least 1.0 ppm. The method may also includes adding an additionalchlorinating agent to the body of water to bring the total chlorinelevel in the body of water back to at least 3.0 ppm but less than 10 ppmafter the free chlorine level of the body of water drops below 0.5 ppm.The method may also include adding a recharging dose of 5,5-dimethylhydantoin to bring the 5, 5-dimethylhydantoin in the body ofwater up to at least 10 ppm.

A further method of maintaining the free chlorine in a body of water forhuman immersion between 0.5 ppm and 1.0 ppm when subject to a batherload that decreases the free chlorine by maintaining the pH in the bodyof water in the range of 7.2 to 7.8 through the addition of pH up or pHDown where pH up comprises sodium bicorbonate and pH down comprisesodium bisulfate. In this method one maintains a temperature of the bodyof water between 65-105 degrees F. and adjusts the alkalinity of thebody of water to between 80 ppm and 120 ppm by either adding eithersodium bicarbonate or a dry or liquid acid to the body of water. In thismethod one adds a chlorinating agent to the body of water to bring thetotal chlorine level in the body of water to at least 3.0 ppm and addssufficient 5-5 dimethylhydantoin to the body of water to bring the levelof free chlorine to about 1.0 ppm at this point one can subject the bodyof water to a bather load where the bather load consumes free chlorinein the body of water without decreasing the free chlorine to less than0.5 ppm by adjusting a chlorine release rate from a dispenser until thefree chlorine level remains above 1 ppm when subject to the bather loadthat consumes at least a portion of the free chlorine available in thebody of water. The above method may include adding at least 3.5 ouncesof DMH per gallon of water to bring the DMH concentration to at least 26ppm.

A method of the invention may also include maintaining a safe freechlorine level in a body of water for recreational use where the freechlorine level at a harmful level measuring the free chlorine level inthe body of water to determine if the free chlorine level in the body ofwater is above a safe level. The method may also include addingsufficient DMH to the body of water to bring the free chlorine down to asafe level by adding DMH to the body of water if the free chlorine levelis above 3.5 ppm to reduce the free chlorine level to below 3.5 ppm.

A method of the invention may include a further method for extending theuseful life of an outdoor pool wherein a chlorinating agent iscontinually or intermittently dispensed into the outdoor pool with thetotal chlorine level of the pool water ranging from 3-10 ppm by addingsufficient DMH to the pool to restore the DMH level to a level thatmaintains the free chlorine below 1.0 ppm. The above method may includeperiodically add additional DMH to the pool to bring the DMH level to atleast 26 ppm. The above method may include having a chlorinating agentdispensed into the pool selected from the group consisting of liquidbleach (NaClO), calcium hypochlorite (CA(ClO)), andTrichloroisocyanauric acid (C3Cl3N3O3).

A method of the invention may include a method of maintaining the freechlorine in a body of water for human immersion between 0.5 ppm and 1.0ppm when subject to a bather load and environmental conditions thatdecreases the free chlorine through maintaining a temperature of thebody of water between degrees 70° F. to 104° F.; sanitizing the body ofwater with a chlorinating agent to render the body of water safe forhuman immersion; adjusting the alkalinity of the body of water tobetween 80 ppm and 120 ppm by adding either sodium bicarbonate to raisethe alkalinity or muriatic acid to lower the alkalinity; maintaining thepH in the body of water in the range of 7.2 to 7.8; adding chlorine tothe body of water to bring the total chlorine level in the body of waterbetween 1-20 ppm; adding DMH to the body of water to bring the level offree chlorine to about 0.5 to 1.0 ppm; and subjecting the body of waterto a bather load where the bather load consumes free chlorine andcombined chlorine in the body of water without decreasing the freechlorine to less than 0.5 ppm level. In the above method one may addchlorine to the body of water to bring the total chlorine level in thebody of water between 1-20 ppm by adding chlorine to the body of waterto bring the total chlorine level in the body of water between 3 and 10ppm. In the above method one may add an additional chlorinating agent tothe body of water to bring the total chlorine level in the body of waterback to between 3 and 10 ppm after the free chlorine level of the bodyof water drops below 0.5 ppm. In the above method one may add arecharging dose of 5, 5-dimethylhydantoin to bring the 5,5-dimethylhydantoin in the body of water up to at least 20 ppm. In theabove method one may maintain a concentration of the 5,5-dimethylhydantoin in the body of water above 20 ppm. The above methodmay include adding an algaecide to the body of water at the sign ofalgae growth. Alternately, the method may include adding an algaecide tothe body of water and an additional chlorinating agent to the body ofwater to bring the total chlorine level in the body of water back tobetween 3.0 and 10 ppm at the sign of algae growth.

A method of the invention may include maintaining the free chlorine in abody of water for human immersion between 0.5 ppm and 1.0 ppm whensubject to a bather load and environmental conditions that decreases thefree chlorine comprises maintaining a temperature of the body of waterbetween degrees 70° F. to 104° F. by sanitizing the body of water with achlorinating agent to render the body of water safe for human immersion;adjusting the alkalinity of the body of water to between 80 ppm and 120ppm by adding either sodium bicarbonate to raise the alkalinity ormuriatic acid to lower the alkalinity; maintaining the pH in the body ofwater in the range of 7.2 to 7.8; loading a first dispensing cartridgecontaining an immediate dispensable DMH therein into an inline dispenserof the body of water to bring a DMH level in the body of water to atleast 26 ppm; loading a second dispensing cartridge containing a timedispensable chlorinating agent therein into the inline dispenser of thebody of water to bring the total chlorine level in a body of watercontaining at least 26 ppm DMH to between 3.0 and 10 ppm total chlorinewith the concentration of DMH maintaining a free chlorine level in theswimming pool body of water to a range 0.5 ppm to 1.0 ppm free chlorine;and then subjecting the body of water to a bather load where the batherload consumes free chlorine and combined chlorine in the body of waterwithout decreasing the free chlorine to less than 0.5 ppm level. In theabove method one may include the step of loading a third dispensingcartridge containing a time dispensable combination chlorinating agentand algaecide therein into the inline dispenser of the body of water inresponse to a decrease of the free chlorine level in the body of waterto less than 0.5 ppm free chlorine to kill existing algae and controlalgae growth in the body of water while bringing the total chlorinelevel in the body of water back to between 3.0 and 10 ppm. The abovemethod may also include loading a third dispensing cartridge containingan immediate dispensable algaecide therein into the inline dispenser ofthe body of water at the sign of algae growth water to kill existingalgae and control algae growth in the body of water. The above methodmay including the loading a third dispensing cartridge containing a timedispensable combination chlorinating agent and algaecide therein intothe inline dispenser of the body of water at the sign of algae growth tokill existing algae and control algae growth in the body of water whilebringing the total chlorine level in the body of water back to between3.0 and 10 ppm. The above may include loading a third dispensingcartridge containing an immediate dispensable DMH therein into theinline dispenser of the body of water to bring the DMH level in the bodyof water up to at least 20 ppm.

A method of the invention may include a method of treating a swimmingpool body of water to maintain a free chlorine in the body of water forhuman immersion between 0.5 ppm and 1.0 ppm when subject to a batherload and environmental conditions that decreases the free chlorine bymaintaining a temperature of the body of water between degrees 70° F. to104° F.; sanitizing the body of water with a chlorinating agent torender the body of water safe for human immersion; adjusting thealkalinity of the body of water to between 80 ppm and 120 ppm by addingeither sodium bicarbonate to raise the alkalinity or muriatic acid tolower the alkalinity; maintaining the pH in the body of water in therange of 7.2 to 7.8; nestably connecting a first dispensing nestablecanister containing an immediate dispensable DMH therein into a chamberof an annular dispensing nestable canister containing water treatmentminerals therein loading the first dispensing nestable canister with theannular dispensing nestable canister into an inline dispersal valve ofthe body of water to bring a DMH level in the body of water to at least26 ppm; replacing said first dispensing nestable canister with a seconddispensing nestable canister containing a time dispensable chlorinatingagent therein to bring the total chlorine level in a body of watercontaining at least 26 ppm DMH to between 3.0 and 10 ppm total chlorinewith the concentration of DMH maintaining a free chlorine level in theswimming pool body of water to a range 0.5 ppm to 1.0 ppm free chlorine;and then subjecting the body of water to a bather load where the batherload consumes free chlorine and combined chlorine in the body of waterwithout decreasing the free chlorine to less than 0.5 ppm level. Theabove method may include replacing the second dispensing nestablecanister with a third dispensing nestable canister containing acombination time dispensable chlorinating agent and algaecide therein inresponse to a decrease of the free chlorine level in the body of waterto less than 0.5 ppm free chlorine to kill existing algae and controlalgae growth in the body of water while bringing the total chlorinelevel in the body of water back to between 3.0 and 10 ppm. The abovemethod may include replacing the second dispensing nestable canisterwith a third dispensing nestable canister containing an immediatedispensable algaecide therein at the sign of algae growth water to killexisting algae and control algae growth in the body of water. The abovemethod may include the replacing the second dispensing nestable canisterwith a third dispensing nestable canister containing a combination timedispensable chlorinating agent and algaecide therein at the sign ofalgae growth to kill existing algae and control algae growth in the bodyof water while bringing the total chlorine level in the body of waterback to between 3.0 and 10 ppm. The above method may replacing thesecond dispensing nestable canister with a fresh first dispensingnestable canister to bring the DMH level in the body of water up to atleast 20 ppm.

The inventions described herein may take various forms includingprepackaged free chlorine maintainer for emptying into a body of waterto maintain a free chlorine level in the body of water between 0.5 ppmand 1.0 ppm when the body of water is subject to a bather load with thefree chlorine maintainer consisting of a chlorinating agent and DMH insolid form where a weight ratio of the DMH to the chlorinating agent inthe body of water is at least 0.5 with the DMH and the chlorinemaintainer either added separately or at the same time. In this examplethe chlorine maintainer may be a one-shot prepackaged free chlorinemaintainer that includes a water dissolvable polyvinyl alcohol filmlocated around the DMH.

The invention may take the form of a spa product for maintaining thefree chlorine level between 0.5 ppm and 1 ppm in a body of water subjectto a bather load with the spa product comprising: a first dispensercontaining a chlorinating agent selected from the group consisting oftrichloroisocyanauric acid (trichlor), potassium dichloroisocyanurate,and sodium dichlorcyanurate (dichlor) with the first dispenser having aport for water access to the chlorinating agent therein when the firstdispenser is placed in the body of water; and a second dispensercontaining dimethylhydantoin with the second dispenser having a port forwater access for release of the dimethylhydantoin into the body ofwater. In this example the spa product may have a weight ratio of DMH inthe second dispenser to the chlorinating agent in the first dispenserranging from 0.31 to 6.3 Or a weight ratio of DMH in the seconddispenser to the chlorinating agent in the first dispenser that variesas a function of time when the chlorinating agent is sodiumdichloroisocyanurate dihydrate.

The invention may take the form of a one-shot prepackaged free chlorinemaintainer for emptying into a body of water to maintain a free chlorinelevel in the body of water between 0.5 ppm and 1.0 ppm when the body ofwater is subject to a bather load with the free chlorine maintainerconsisting of a chlorinating agent in solid form and DMH in solid formwhere a weight ratio of the DMH to the chlorinating agent is at least0.5 and the chlorinating agent and the DMH are either added separatelyor at the same time to the body of water. As an example the one-shotprepackaged free chlorine maintainer containing 5,5-dimethylhydantoin issufficient to raise the 5,5-dimethylhydantoin level to 10 to 20 ppm in abody of water where a total chlorine concentration is at least 3.0 ppmwith the chlorinating agent comprising sodium dichloroisocyanurate orsodium trichloroisocyanurate.

The invention may take the form of a free chlorine maintainer for a bodyof water wherein a concentration of the free chlorine maintainerconsists of a chlorinating agent and 5,5-dimethylhydantoin with the bodyof water having at least 5.0 grams of the free chlorine maintainer pergallon of water where the chlorinating agent is selected from the groupconsisting of trichloroisocyanauric acid, potassiumdichloroisocyanurate, sodium dichloroisocyanurate as anhydrous ordihydrate form, calcium hypochlorite, lithium hypochlorite and sodiumhypochlorite. For example, The prepackaged free chlorine maintainer fora body of water ranging between 100 to 600 gallons wherein the weight ofdimethylhydantoin added to the body of water is at least 17 grams butless than 115 grams.

The invention may take the form of a pool product for maintaining a freechlorine level in a range of 0.5 ppm to 1.0 ppm in a pool wherein thepool is subject to a periodic bather load and the pH of the pool ismaintained between 7.2 pH and 7.8 pH comprising: a first dispenserhaving a compartment containing a chlorinating agent for a placing in anoutdoor pool; and a second dispenser having a compartment containing 5,5-dimethylhydantoin wherein a release of the chlorinating agent from thefirst dispenser increases the total chlorine to at least 3.0 ppm and arelease of the 5, 5-dimethylhydantoin from the second dispenser in thepool lowers the free chlorine level between 0.5 ppm and 1.0 ppm. In thisexample the first dispenser containing the chlorination agent is placedin the body of water before the second dispenser containing thedimethylhydantoin is placed in the body of water.

The invention may take the form of a spa for absorbing a bather loadwithout having to increase a free chlorine level in the body of waterthrough addition of an additional chlorinating agent wherein the body ofwater: is between 65-105° F. with a pH in the range of 7.2 to 7.8; hasan alkalinity in the range of 80 ppm to 120 ppm and a measured level oftotal chlorine comprising a dimethylhydantoin associated chlorine of atleast 3.0 ppm and a measured level of free chlorine in a range of 0.5ppm and 1.0 ppm after the body of water has been subjected to acombination of a chlorinating agent and dimethylhydantoin but before thebody of water is subject to the bather load wherein the bather loadabsorbs the free chlorine in the body of water as the dimethylhydantoinconverts the dimethylhydantoin associated chlorine to the free chlorineto thereby maintain the free chlorine in the range of 0.5 ppm to 1.0 ppmas long as the bather load chlorine demand does not exceed thedimethylhydantoin associated chlorine.

The invention may take the form of a free chlorine maintained system forabsorbing a bather load without having to increase a free chlorine levelin the body of water through addition of an additional chlorinatingagent where the body of water has: a temperature that ranges from 60° F.to 120° F., a pH that ranges from 7.2 to 7.8; an alkalinity that rangesfrom 80 ppm to 120 ppm; a measured level of total chlorine comprising adimethylhydantoin associated chlorine that is at least 3.0 ppm; and afree chlorine maintainer consisting of a chlorinating agent anddimethylhydantoin where a measured level of free chlorine ranges from0.5 ppm to 1.0 ppm both before and after the body of water is subjectedto the bather load and without addition of additional chlorine to thebody of water. In this example the concentration of thedimethylhydantoin in the body of water ranges from 20 ppm to 200 ppm.Also, in this example the concentration of total chlorine in the body ofwater is at least 3.0 ppm.

The invention may take the form of a set of dispensing cartridges forplacing in a back-to-back condition in an inline dispenser comprising: afirst dispensing cartridge having a bottom inlet and a bottom outlet andcontaining a time dispensable chlorinating agent therein; and a seconddispensing cartridge having a bottom inlet and a bottom outlet and animmediate dispensable DMH therein in sufficient amount to increase theconcentration of DMH to a level that reduces a free chlorine level to arange 0.5 ppm to 1.0 ppm. In this example the set of dispensingcartridges may include a further dispensing cartridge containing analgaecide wherein the algaecide is dispensed into the body of water inresponse to a decrease of the free chlorine level to less than 0.5 ppm.Also in this example The set of dispensing cartridges contain sufficientchlorine to bring a total chlorine in the body of water in the range of3-10 ppm.

The invention may take the form of a prepackaged free chlorinemaintainer for use in a body of water that has been sanitized with achlorinating agent to render the body of water safe for human immersion,the free chlorine maintainer including: a source of chlorine in solidform, the source of chlorine fully dissolvable in the body of water tobring the total chlorine level in the body of water to between 3 and 10ppm; and a source of DMH in solid form, the source of DMH fullydissolvable in the body of water to bring the level of DMH in the bodyof water above 10 ppm while maintaining a level of free chlorine in thebody of water between about 0.5 to 1.0 ppm. In this example theinvention may include a source of an algaecide in solid form,dissolvable in the body of water to kill existing algae and controlalgae growth in the body of water. In this example the prepackaged freechlorine maintainer may include a water dissolvable polyvinyl alcoholfilm housing encompassing the free chlorine maintainer. In this examplethe body of water may comprises an outdoor swimming pool. In thisexample the prepackaged free chlorine maintainer is used in body ofwaters that ranges between 10,000 to 15,000 gallons, between 4,000 to6,000 gallons or between 100 to 600 gallons. In this example the body ofwater comprises a spa or hot tub.

The invention may take the form a prepackaged free chlorine maintainerfor use in a body of water that has been sanitized with a chlorinatingagent to render the body of water safe for human immersion, the freechlorine maintainer including a recharging dose of chlorine in solidform, the recharging dose of chlorine dissolvable in the body of waterto bring the total chlorine level in the body of water to between 3 and10 ppm; and a recharging dose of DMH in solid form, the recharging doseof DMH dissolvable in the body of water to bring the level of DMH in thebody of water above 10 ppm.

The invention may take the form an outdoor swimming pool free chlorinemaintaining dispenser for use in an outdoor swimming pool body of waterthat has been sanitized with a chlorinating agent to render the body ofwater safe for human immersion and subject to a periodic bather load andenvironmental conditions, the free chlorine maintaining dispenserincluding: a first housing having a water accessible compartmentcontaining a chlorinating agent releasable into the body of water tomaintain the total chlorine level in the body of water above 4 ppm; asecond housing having a water accessible compartment containing a sourceof DMH dissolvable in the body of water to maintain the level of DMH inthe body of water above 10 ppm while maintaining a level of freechlorine in the body of water between about 0.5 to 1.0 ppm. As anexample the free chlorine maintaining dispenser may including a thirdhousing having a water accessible compartment containing a source of analgaecide in solid form, the source of algaecide dissolvable in the bodyof water to kill existing algae and control algae growth in the body ofwater. As a further example the third housing may comprise a detachablethird housing.

The invention may take the form a prepackaged free chlorine maintainerfor use in a body of water that has been sanitized with a chlorinatingagent to render the body of water safe for use as potable water, thefree chlorine maintainer including: a source of chlorine in solid form,the source of chlorine fully dissolvable in the body of water to bringthe total chlorine level in the body of water to between 3 and 10 ppm;and a source of DMH in solid form, the source of DMH fully dissolvablein the body of water to bring the level of DMH in the body of waterabove 10 ppm while maintaining a level of free chlorine between about0.5 to 1.0 ppm.

The invention may take the form of a swimming pool free chlorinemaintaining kit for use in an inline dispenser of a swimming pool bodyof water that has been sanitized with a chlorinating agent to render thebody of water safe for human immersion and subject to a periodic batherload and environmental conditions, the swimming pool free chlorinemaintaining kit including: a first dispensing cartridge having a bottominlet and a bottom outlet and an immediate dispensable DMH therein insufficient amount to bring a DMH level in the swimming pool body ofwater to at least 26 ppm and a second dispensing cartridge having abottom inlet and a bottom outlet and containing a time dispensablechlorinating agent therein to bring the total chlorine level in aswimming pool body of water containing at least 26 ppm DMH to between3.0 and 10 ppm total chlorine with the concentration of DMH maintaininga free chlorine level in the swimming pool body of water to a range 0.5ppm to 1.0 ppm free chlorine. In this example the swimming pool freechlorine maintaining kit may include a third dispensing cartridge havinga bottom inlet and a bottom outlet and containing a time dispensablecombination chlorinating agent and algaecide, the combinationchlorinating agent and algaecide dispensable into the swimming pool bodyof water in response to a decrease of the free chlorine level in theswimming pool body of water to less than 0.5 ppm free chlorine to killexisting algae and control algae growth in the body of water whilebringing the total chlorine level in the swimming pool body of waterback to between 3.0 and 10 ppm. Also as an example The swimming poolfree chlorine maintaining kit may include a third dispensing cartridgehaving a bottom inlet and a bottom outlet and containing an immediatedispensable algaecide therein, the algaecide dispensable into theswimming pool body of water at the sign of algae growth to kill existingalgae and control algae growth in swimming pool body of water. As afurther example The swimming pool free chlorine maintaining kit mayinclude a third dispensing cartridge having a bottom inlet and a bottomoutlet and containing a time dispensable combination chlorinating agentand algaecide, the combination chlorinating agent and algaecidedispensable into the swimming pool body of water at the sign of algaegrowth to kill existing algae and control algae growth in the swimmingpool body of water while bringing the total chlorine level in theswimming pool body of water back to between 3.0 and 10 ppm.

The invention may take the form of swimming pool water treatment systemfor use in an inline dispenser of a swimming pool body of water that hasbeen sanitized with a chlorinating agent to render the body of watersafe for human immersion and subject to a periodic bather load andenvironmental conditions, the swimming pool water treatment systemincluding: a dispersal valve for directing water therethrough, thedispersal valve having an internal chamber; a first dispensing nestablecanister having a bottom inlet and a bottom outlet and an immediatedispensable DMH therein in sufficient amount to bring a DMH level in theswimming pool body of water to at least 26 ppm; a second dispensingnestable canister having a bottom inlet and a bottom outlet andcontaining a time dispensable chlorinating agent therein to bring thetotal chlorine level in a swimming pool body of water containing atleast 26 ppm DMH to between 3.0 and 10 ppm total chlorine with theconcentration of DMH maintaining a free chlorine level in the swimmingpool body of water to a range 0.5 ppm to 1.0 ppm free chlorine; and anannular dispensing nestable canister having a bottom inlet and a bottomoutlet and containing water treatment minerals therein, the annulardispensing nestable canister having a chamber for nestably supportingthe first dispensing nestable canister or the second dispensing nestablecanister therein with the annular dispensing nestable canister and thedispensing nestable canister supported in the internal chamber of thedispersal valve to provide the dispersal valve with multiple watertreatment dispersants for dispensing into a swimming pool body of water.As an example the swimming pool water treatment system may include athird dispensing nestable canister nestably supportable within thechamber of the annular dispensing nestable canister and having a bottominlet and a bottom outlet and containing a combination time dispensablechlorinating agent and algaecide, the combination chlorinating agent andalgaecide dispensable into the swimming pool body of water in responseto a decrease of the free chlorine level in the swimming pool body ofwater to less than 0.5 ppm free chlorine to kill existing algae andcontrol algae growth in the body of water while bringing the totalchlorine level in the swimming pool body of water back to between 3.0and 10 ppm. As a further example The swimming pool water treatmentsystem may including a third dispensing nestable canister nestablysupportable within the chamber of the annular dispensing nestablecanister and having a bottom inlet and a bottom outlet and containing animmediate dispensable algaecide therein, the algaecide dispensable intothe swimming pool body of water at the sign of algae growth to killexisting algae and control algae growth in swimming pool body of water.A further example of the swimming pool water treatment system mayincluding a third dispensing nestable canister nestably supportablewithin the chamber of the annular dispensing nestable canister andhaving a bottom inlet and a bottom outlet and containing a combinationtime dispensable chlorinating agent and algaecide, the combinationchlorinating agent and algaecide dispensable into the swimming pool bodyof water at the sign of algae growth to kill existing algae and controlalgae growth in the swimming pool body of water while bringing the totalchlorine level in the swimming pool body of water back to between 3.0and 10 ppm.

In the above evaluation wherever possible tests were conducted underfield conditions as opposed to lab conditions in order ensure that theintegrity of the results when the method and apparatus are used underfield conditions.

We claim: 1-9. (canceled)
 10. A set of dispensing cartridges for placingin a back-to-back condition in an inline dispenser comprising: a firstdispensing cartridge having a bottom inlet and a bottom outlet andcontaining a time dispensable chlorinating agent therein; and a seconddispensing cartridge having a bottom inlet and a bottom outlet and animmediate dispensable DMH therein in sufficient amount to increase theconcentration of DMH to a level that reduces a free chlorine level to arange 0.5 ppm to 1.0 ppm.
 11. The set of dispensing cartridges of claim10 including a further dispensing cartridge containing an algaecidewherein the algaecide is dispensed into the body of water in response toa decrease of the free chlorine level to less than 0.5 ppm.
 12. The setof dispensing cartridges of claim 10 wherein sufficient chlorine isdispensed into the body of water to bring a total chlorine in the bodyof water in the range of 3-10 ppm.
 13. (canceled)
 14. (canceled) 15.(canceled)
 16. the prepackaged free chlorine maintainer of claim 13 foruse in a body of water that has been sanitized with a chlorinating agentto render the body of water safe for human immersion, the free chlorinemaintainer including: a recharging dose of chlorine in solid form, saidrecharging dose of chlorine dissolvable in said body of water to bringthe total chorine level in the body of water to between 3 and 10 ppm;and a recharging dose of DMH in solid form, said recharging dose of DMHdissolvable in said body of water to bring the level of DMH in the bodyof water above 10 ppm.
 17. An outdoor swimming pool free chlorinemaintaining dispenser for use in an outdoor swimming pool body of waterthat has been sanitized with a chlorinating agent to render the body ofwater safe for human immersion and subject to a periodic bather load andenvironmental conditions, the free chlorine maintaining dispenserincluding: a first housing having a water accessible compartmentcontaining a chlorinating agent releasable into the body of water tomaintain the total chlorine level in the body of water above 4 ppm; asecond housing having a water accessible compartment containing a sourceof DMH dissolvable in said body of water to maintain the level of DMH inthe body of water above 10 ppm while maintaining a level of freechlorine in the body of water between about 0.5 to 1.0 ppm.
 18. The freechlorine maintaining dispenser of claim 17 including a third housinghaving a water accessible compartment containing a source of analgaecide in solid form, said source of algaecide dissolvable in saidbody of water to kill existing algae and control algae growth in saidbody of water.
 19. The free chlorine-maintaining dispenser of claim 49wherein said third housing comprises a detachable third housing.
 20. Aswimming pool free chlorine maintaining kit for use in an inlinedispenser of a swimming pool body of water that has been sanitized witha chlorinating agent to render the body of water safe for humanimmersion and subject to a periodic bather load and environmentalconditions, the swimming pool free chlorine maintaining kit including: afirst dispensing cartridge having a bottom inlet and a bottom outlet andan immediate dispensable DMH therein in sufficient amount to bring a DMHlevel in the swimming pool body of water to at least 26 ppm; and asecond dispensing cartridge having a bottom inlet and a bottom outletand containing a time dispensable chlorinating agent therein to bringthe total chlorine level in a swimming pool body of water containing atleast 26 ppm DMH to between 3.0 and 10 ppm total chlorine with theconcentration of DMH maintaining a free chlorine level in the swimmingpool body of water to a range 0.5 ppm to 1.0 ppm free chlorine.
 21. Theswimming pool free chlorine maintaining kit of claim 20 including athird dispensing cartridge having a bottom inlet and a bottom outlet andcontaining a time dispensable combination chlorinating agent andalgaecide, the combination chlorinating agent and algaecide dispensableinto the swimming pool body of water in response to a decrease of thefree chlorine level in the swimming pool body of water to less than 0.5ppm free chlorine to kill existing algae and control algae growth insaid body of water while bringing the total chlorine level in theswimming pool body of water back to between 3.0 and 10 ppm.
 22. Theswimming pool free chlorine maintaining kit of claim 20 including athird dispensing cartridge having a bottom inlet and a bottom outlet andcontaining an immediate dispensable algaecide therein, the algaecidedispensable into the swimming pool body of water at the sign of algaegrowth to kill existing algae and control algae growth in swimming poolbody of water.